Two simulated specific intensity functions at ν_obs = 150 MHz, assuming synchrotron radiation from merger and accretion shocks (as in Hoeft & Brüggen 2007) in LSS at z = 0.045. Top: primordial scenario for magnetogenesis, starting from B_IGM = 1 nG in the Early Universe. (In contrast, the simulation underlying this article’s predictions starts at B_IGM = 0.1 nG.) Bottom: galactic scenario for magnetogenesis, in which seeding occurs through AGN outflows and supernova winds. See Gheller & Vazza (2020) for details on these scenarios.